Yeah,
I suspect that is the part that goes out and puts these babies "UpSide Down".
I got lucky and got the whole Antenna at a local recyclers for $12.00 USD.
'Got pockets of Money? "Google" Walter Odemer. In California he rebuilds
He'll charge about $125.00 USD ,I think.
http://www.salvageyards.ws/salvage_yards_in_nc-2.shtml